Tape reinforced grain door panel



Deco 13, 1966 BLATT 3,291,395

TAPE REINFORCED GRAIN DOOR PANEL Filed Dec. 31. 1965 2 Sheets-Sheet l ATTORNEY Dec 13, 1966 D. H. BLATT 3,29LWS TAPE REINFORCED GRAIN DOOR PANEL Filed Dec. 51, 1963 rumu o\ mums 2 Sheets-Sheet 2 INVENTOR.

99 VIP H- B HTT H TTOQIUEV nited States Patent 3,291,195 TAPE REHNFORQED GRAIN DOOR PANEL David H. Elatt, Meirose Park, Pa., assignor, by mesne assignments, to Walnut Industries Company, Philadelphia, Pa, a partnership Filed Dec. 31, 1963, Ser. No. 334,835 3 Claims. (Cl. 160-368) This invention relates generally to closure and retaining panels, and more particularly, this invention relates to reinforced disposable paperboard panels which may be used as retaining members and closure doors for railroad box cars or trucks and the method of installing the same, a particular application being that of a railroad box car grain door. This application is a continuation in-part of my application Serial No. 192,819, filed May 7, 1962, now abandoned, the present invention repre senting an improvement over that disclosed in the earlier filed case.

In the past, grain doors for railroad box cars were originally made of timbers nailed across the door frame opening. More recently grain doors have been made of corrugated paper paneling reinforced with steel strapping, which doors were installed across the door frame opening by nailing through the ends of the steel straps into the door frame side posts. The procedure of nailing through the reinforcing steel strapping into the door frame is of course necessary so that the grain load against the grain door is carried by the steel straps since it is apparent that merely nailing through the corrugated paperboard into the side posts would cause the grain door to be torn out of the door under load.

Inasmuch as the grain doors of this type are only temporarily installed for a given trip and are then removed and disposed of so that the car can be used for other purposes, these railroad grain cars over a period of several months are subjected to the installation and removal of many such grain doors resulting in the splintering of the door frame side posts due to the repeated nailings and strippings to which they are subjected. It has been the experience of the railroads that cars used in this manner must be taken out of service every few months and put into the repair shop for replacement of the door frame side posts. This of course creates an operating loss not only because of the time and materials involved in replacing the door frame posts but also because the railroad car is unavailable for use until the repairs are carried out, and this operating loss must be charged to overhead. Grain doors made and installed in accordance with the principles of the present invention eliminate this rapid destruction of the door frame side posts, thereby eliminating the need for frequent repairs to the grain car and the out of service time. Consequently, the operating overhead associated with these factors is disposed of and substantial annual revenue savings are realized.

The previously known types of reinforced paperboard grain doors also tended to bulge centrally outward under load so that in a severe case the bulged grain door engaged the inside of the sliding outer doors of a railroad car and caused these doors to jam. When the outer doors were thereafter forced open at the destination point, the grain door would be torn apart and the load discharged. A very important feature of the present invention is the construction and installation of the grain doors in such manner as to substantially eliminate the bulging thereof. Briefly, the invention contemplates a grain door fabricated of laminated paperboard including a plurality of spaced apart parallel extending non-metallic flexible reinforcing tapes bonded into the structure between laminations thereof and immediately underlying window areas cut through one of the paperboard laminations so as to 3,2i,l95 Patented Dec. 13, 1966 ice expose a length of each of the tapes at opposite ends of the grain door structure. The grain doors so constructed are secured to the car door frames by means of a bonding agent in such manner that the exposed end lengths of the reinforcing tapes are strongly secured to the door frame. Additionally, the grain doors are provided with top and bottom flaps firmly securable to rigid members extending transversely across the car doorway to prevent bulging of the grain door at top and bottom, and hence substantially eliminate bulging altogether.

It is a principal object of this invention to provide a novel non-bulging grain door structure and method of installation which allow the grain doors to be installed and removed with no attendant destructive effects upon the door frame across which the grain door is installed.

Another object of this invention is to provide a novel non-bulging grain door structure which may be adhesively secured to a grain car door frame in such manner that the full grain load of the car is sustainable with a high safety factor.

Still another object of this invention is to provide a novel tape reinforced paperboard grain door adhesively secured to the door frame of a grain car so that the weight of the grain load is borne primarily by the reinforcing tapes adhesively secured at opposite ends to the door frame side posts.

The foregoing and other objects of the invention will become clear from a reading of the following specification in conjunction with an examination of the appended drawings, wherein:

FIGURE 1 illustrates in plan view one side of a plurality of tape reinforced corrugated paperboard grain doors having top and bottom flaps and windows cut through one of the paper laminations to expose portions of the underlying tapes;

FIGURE 2 is a fragmentary perspective view of one of the grain doors of FIGURE 1 shown in a folded form for storage and transportation;

FIGURE 3 is an enlarged fragmentary detail of an end portion of the left hand grain door structure of FIG- URE 1 enclosed in the phantom circle with the laminated layers fragmented away to show the laminated construction of the paper layers and tapes;

FIGURE 4 is a cross sectional view through the structure of FIGURE 1 as would be seen when viewed along the line 4-4 of the enlarged fragmentary view of FIG- URE 3;

FIGURE 5 is an enlarged vertical sectional view through the installed grain door of FIGURE 7 as would be seen when viewed along the line 5-5 of FIGURE 7;

FIGURE 6 is a perspective view of a grain car door frame area, as viewed from the inside out, illustrating the beginning steps in the installation of the grain door structure in accordance with the novel method of the invention; and

FIGURE 7 shows the completely installed grain door shown partially installed in FIGURE 6.

In the several figures, like elements are denoted by like reference characters.

Turning now to an examination of the figures, consider first the showings of FIGURES 1 to 4 which illustrate the structural aspects of a flexible tape reinforced paperboard grain door according to the invention. The grain door is designated generally as 20 and basically consists of a corrugated paper medium or core 21 having transversely extending corrugations 22, as best seen in FIG- URE 4; a first paper facing or liner 23 the inner surface of which is glued to the troughs of the corrugations 22 of the core 21; a second paper facing or liner 24 the inner surface of which is glued to the crests of the corrugations of the corrugated core 21; and a plurality of non-metallic flexible tapes 25 sandwiched between and also adhesively secured to the corrugated core 21 and facing 24. The tapes 25 may be of any desired construction and nonmetallic material having the requisite flexibility, tensile strength and lightness in weight, as for example woven or unwoven tapes of fabric or plastic. A preferred form of tape is that of the -weftless type now generally available on the market, which is made by securing a plurality of high tenacity rayon tire cords together in side by side relation, the cords being bonded tog-ether by a heat-sealable composition which makes it possible to heat-seal or otherwise adhesively bond the tape to the paper of the grain door. Further, the tape is such as lends itself to secure adhesive bonding to any surface coated with contact adhesive.

It will be observed, as best shown in FIGURES l and 3, that the paper facing 24 is provided with a plurality of spaced apart windows or cut outs 26 located so as to overlie the tapes 25 at their ends. The corrugated paperboard grain door 20 may be readily fabricated with well known paper combining machinery used in the production of corrugated paperboard, the modifications to such equipment that are necessary being the provision of punch apparatus for knocking out the windows in the paper facing 24 as it is fed from its supply roll, means for feeding the fabric tapes 25 into the combining machinery at the proper locations to provide for their registry with the windows 26 of the facing 24, and scoring apparatus to provide the scored fold lines 27 and 28 which divide the grain doors into three adjacent panel sections designated as 29, 30 and 31. As best seen in FIGURES 2 and 4 the running width of the windowed facing 24 is chosen greater than that of the core 21 and facing 23 in order to provide the flap 24a at the upper edge of the grain doors for a purpose to be subsequently described.

The corrugated paper core 21, the paper facings 23 and 24 and the fabric tapes 25 are all continuously fed into the combining machinery from large supply rolls and emerge as a continuous length of panelling. As the panelling is formed in its finished state it is scored at 27 and 28 and fed into shearing apparatus which cuts it along lines 32 into predetermined lengths of a desired size, the cut lengths emerging from the shearing apparatus as the finished grain doors 20. It will be recognized that the end windows 26 are formed by the shearing apparatus when the latter cuts centrally through the elongated openings designated as 33 so that one half of such an opening appears as the end window of one grain door 20 while the other half forms the end window of the next successively produced grain door 20.

Provision of the scored fold-lines 27 and 28 which subdivide the grain door 20 into the panels 29, 30 and 31 allows the finished grain door 20 to be folded about the score lines to form a compact and readily carried package as shown in FIGURE 2. The utility of providing the fold-lines will be appreciated from the fact that such grain doors are generally about seven feet in overall height and nine to twelve feet in length, such size panels :being unwieldy and not readily manipulable by a single person when formed in a nonfoldable sheet of the foregoing dimensions.

As will be observed in the showing of FIGURE 1, the spacing between successively adjacently positioned tapes is not constant but is smaller in the panel 30 than in the panel 31. This is done because panel 30 is the lowermost vertical panel in the installed grain door and is subjected to the greatest loading stress, the loading stress decreasing with increasing elevation. The lowermost panel 29 is a floor flap provided to insure that the grain at floor level within the grain car cannot force itself outward through the doorway beneath the grain door lower edge and also anchoring the lower edge of the grain door throughout its extent to prevent bulging.

Turning now to the showings of FIGURES through 7 for an understanding of the novel method of installation of the grain doors previously described, there will be seen a fragment of the interior region of a grain car showing the car floor 34 and one wall 35 within which is formed a doorway 36 including the side posts 37. The grain door 20 is installed across the doorway 36 in the following manner. First, the inside faces of the doorway side posts 37 and the edge of the floor 34 which extends across the doorway 36 are all liberally coated as at 38 with a contact adhesive. In a similar manner, the opposite ends of the grain door panels and the floor flap 29 are also coated with the contact adhesive as shown at 39, care being exercised to insure that the tapes 25 which are exposed through the end windows 26 are thoroughly coated. The grain door is now positioned as shown in FIGURE 6 with the floor flap 29 placed firmly down upon the floor 34 and with the lower door panel 30 pressed vertically against the adhesively coated surface of the side posts 37. The grain door is then flipped upward as shown in FIGURE 7 and the coated ends of the top panel 31 are pressed against the coated side posts.

The installer insures proper seating of the door edges against the side posts by applying pressure thereto with either a roller device or by tapping with a mallet. The contact adhesive coatings 38 and 39 fuse together upon contact and pressure to form a homogeneous layer as indicated at 3839 in the sectional view of FIGURE 5. Next, the bottom timber 40 is pressed down upon the grain door floor flap panel 29 and against the lower panel 30 to firmly press the floor flap 29 and panel 30 respectively against the floor 34 and against wall 35 laterally of the door posts 37, the timber being secured by nails 41 as seen in FIGURES 5 and 7. The top timber 42 is next disposed across the doorway 36 against the grain door at the upper edge of upper panel 31 and secured by means of nails 43 driven therethrough as seen in FIGURE 5. This leaves the flap 24a projecting loosely upward above the timber 42. The flap 24a and timber 42 are then coated with the contact adhesive, and the flap 24a is pulled around and pressed firmly against the timber 42 to bring the adhesive coatings into contact to form a homogeneous layer 44 seen in FIGURE 5. The upper edge of the grain door is thus made rigid completely across the doorway opening and is prevented from bulging under load, the timber 42 being of sufficient strength for this purpose.

Any suitable contact adhesive, as, for example, synthetic rubber resin adhesives such as are now commercially available, may be utilized in practicing the novel method of grain door installation as hereinbefore described provided it exhibits a sufficient strength when subjected to shear, this being the type of stress set up in the adhesive bond when the grain car is loaded and the grain presses outward against the inside face of the installed grain door. One such adhesive which has been found to be satisfactory in actual use is a synthetic rubber resin adhesive designated as D-22O contact adhesive marketed by the Armstrong Industrial Division of the Armstrong Cork Company.

When the grain car has reached its destination, it is unloaded by simply piercing the grain door panelling at a point or points below the top brace 42 to provide an opening through which the grain may discharge. Then, when the unloading has been completed the wood braces 40 and 42 are removed, following which the tapes may be severed intermediate their lengths and the remnants of the grain door peeled away from the surfaces to which it was adhesively bonded.

Having now described my invention in connection with a particularly illustrated embodiment thereof it will be appreciated that variations and modifications of the same may now occur from time to time to those persons normally skilled in the art without departing from the essential spirit or scope of the invention, and accordingly, 1t 13 intended to claim the same broadly as well as specifically as indicated by the appended claims.

What is claimed as new and useful is:

1. A grain door installation in a grain car for closing a door frame opening therein comprising in combination, a main panel section vertically disposed again-st and fixedly secured along its side edges to the opposite sides of the door frame, a floor flap integral with and extending substantially the full width of the main panel substantially straight thereto along the lower edge of the latter seated down upon and fixedly secured to the floor of the grain car, a rigid elongated member fixedly secured across the door frame opening to back up the grain door at the upper edge of its main panel, said main panel section and floor flap of the grain door being formed of corrugated paperboard having an inner core of corrugated paper and paper facings adhesively secured to opposite surfaces of said core, and a top flap secured to and extending upwardly beyond the upper edge of the corrugated inner core of the main panel substantially the full width of the latter as a continuati-on of one of said paper facings of the corrugated board, said top flap being turned tautly over the top of and fixedly secured to the rigid back-up member for substantially its full width to thereby secure the upper edge of the grain door against outward deflection.

2. A grain door installation as defined in claim 1 wherein said main panel section includes a plurality of spaced apart parallel flexible non-metallic tapes extending linearly of the grain door for the full width thereof and transversely to the corrugations of the corrugated core and being sandwiched between and bonded to said corrugated core and that one of said paper fa-cings which includes said top flap, said last mentioned paper facing being provided with windows along its marginal edges at the opposite side edges of the grain door with such windows disposed respectively in overlying registry with the end portions of the said flexible tapes to expose the latter for a distance inward from the side edges of the grain door.

3. A grain door installation as defined in claim 1 wherein said main panel section includes a plurality of spaced apart parallel flexible non-metallic tapes extending linearly of the grain door for the full width thereof and transversely to the corrugations of the corrugated core and being sandwiched between and bonded to said corrugated core and that one of said paper facings which includes said top flap, said iast mentioned paper facing being provided with windows along its marginal edges at the opposite side edges of the grain door with such windows disposed respectively in overlying registry with the end por tions of the said flexible tapes to expose the latter for a distance inward from the side edges of the grain door, and wherein said exposed portions of the flexible tapes and the intervening portions of the windowed facing which extend vertically between the exposed tapes along each of the opposite sides of the main panel are respectively adhesively secured to the wall surfaces at the corresponding opposite sides of the door frame.

References Cited by the Examiner UNITED STATES PATENTS 1,241,146 9/1917 Perry 156-71 1,994,262 3/1935 Winding 156-71 2,739,635 3/1956 Seaborne et a1 160-368 2,794,761 6/1957 Williamson 160-368 2,797,749 7/1957 Ford et al 160-368 2,966,213 12/1960 Ford 160-368 2,966,214 12/1960 Ford 160-368 3,025,908 3/196'2 Ford et al 160-368 3,094,447 6/1963 Chamberlain 156-71 3,099,314 7/1963 Talbot et al. 160-368 3,156,604 11/1964 Blatt 160-368 HARRISON R. MOSELEY, Primary Examiner.

P. C. KANNAN, Assistant Examiner, 

1. A GRAIN DOOR INSTALLATION IN A GRAIN CAR FOR CLOSING A DOOR FRAME OPENING THEREIN COMPRISING IN COMBINATION, A MAIN PANEL SECTION VERTICALLY DISPOSED AGAINST AND FIXEDLY SECURED ALONG ITS SIDE EDGES TO THE OPPOSITE SIDES OF THE DOOR FRAME, A FLOOR FLAP INTEGRAL WITH AND EXTENDING SUBSTANTIALLY THE FULL WIDTH OF THE MAIN PANEL SUBSTANTIALLY STRAIGHT THERETO ALONG THE LOWER EDGE OF THE LATTER SEATED DOWN UPON AND FIXEDLY SECURED TO THE FLOOR OF THE GRAIN CAR, A RIGID ELONGATED MEMBER FIXEDLY SECURED ACROSS THE DOOR FRAME OPENING TO BACK UP THE GRAIN DOOR AT THE UPPER EDGE OF ITS MAIN PANEL, SAID MAIN PANEL SECTION AND FLOOR FLAP OF THE GRAIN DOOR BEING FORMED OF CORRUGATED PAPERBOARD HAVING AN INNER CORE OF CORRUGATED PAPER AND PAPER FACINGS ADHESIVELY SECURED TO OPPOSITE SURFACES OF SAID CORE, AND A TOP FLAP SECURED TO AND EXTENDING UPWARDLY BEYOND THE UPPER EDGE OF THE CORRUGATED INNER CORE OF THE MAIN PANEL SUBSTANTIALLY THE FULL WIDTH OF THE LATTER AS A CONTINUATION OF ONE OF SAID PAPER FACINGS OF THE CORRUGATED BOARD, SAID TOP FLAP BEING TURNED TAUTLY OVER THE TOP OF AND FIXEDLY SECURED TO THE RIGID BACK-UP MEMBER FOR SUBSTANTIALLY ITS FULL WIDTH TO THEREBY SECURE THE UPPER EDGE OF THE GRAIN DOOR AGAINST OUTWARD DEFLECTION. 